Method to automatically adjust a trailer brake controller

Abstract

A vehicle brake system includes a brake control device, a vehicle acceleration sensor, and a trailer brake controller. The trailer brake controller outputs an initial trailer brake torque demand based on an input received from the brake control device and adjusts the initial trailer brake torque demand to converge a signal from the vehicle acceleration sensor to an expected negative acceleration value correlated with the input from the brake control device.

What is claimed is: 
     
       1. A vehicle brake system, comprising:
 a vehicle brake pedal; 
 a position sensor coupled with the vehicle brake pedal, measuring a position of the vehicle brake pedal within a range of movement thereof, and outputting a signal corresponding with the position of the vehicle brake pedal; 
 a vehicle acceleration sensor outputting a vehicle acceleration signal; and 
 a trailer brake controller:
 connected with the position sensor and the vehicle acceleration sensor; 
 outputting an initial trailer brake torque demand signal readable by an external electronic brake unit correlated with the signal from the position sensor; 
 determining an expected negative acceleration value correlated with the signal from the position sensor using one of a predetermined formula or a table; 
 receiving a vehicle acceleration signal from the acceleration sensor; and 
 adjusting the initial trailer brake torque demand signal to converge the vehicle acceleration signal to the expected negative acceleration value. 
 
 
     
     
       2. The brake system of  claim 1 , wherein the signal output by the position sensor is proportionate to the position of the vehicle brake pedal with respect to the range of movement. 
     
     
       3. The brake system of  claim 1 , wherein the controller adjusts the initial trailer brake torque demand according to a closed loop control scheme to one of increase or decrease a trailer brake torque demand corresponding with the signal. 
     
     
       4. The brake system of  claim 3 , wherein the closed loop control scheme is a proportional-integral-derivative control scheme. 
     
     
       5. The brake system of  claim 1 , wherein the predetermined formula provides the expected negative acceleration value as a function of the signal from the position sensor. 
     
     
       6. The brake system of  claim 5 , wherein the expected negative acceleration function is adjustable based on a user input as an additional variable in the predetermined formula. 
     
     
       7. The brake system of  claim 1 , wherein the vehicle acceleration sensor is a component of a vehicle antilock brake control system. 
     
     
       8. The brake system of  claim 1 , wherein the vehicle acceleration sensor is a module that receives an input from a vehicle velocity sensor over time to determine acceleration. 
     
     
       9. A vehicle, comprising:
 a vehicle brake pedal; 
 a position sensor coupled with the vehicle brake pedal, measuring a position of the vehicle brake pedal within a range of movement thereof, and outputting a signal corresponding with the position of the vehicle brake pedal; 
 a vehicle acceleration sensor outputting a vehicle acceleration signal; 
 an external communication coupling; and 
 a trailer brake controller:
 connected with the position sensor and the vehicle acceleration sensor; 
 receiving the signal from the position sensor and deriving an initial trailer brake torque demand signal correlated with the signal from the position sensor, the initial trailer brake torque demand signal being readable by an external electronic brake unit; 
 outputting the initial trailer brake torque demand signal to the communication coupling; 
 determining an expected negative acceleration value correlated with the signal from the position sensor using one of a predetermined formula or a table; and 
 adjusting the initial trailer brake torque demand signal to converge a signal from the acceleration sensor to the expected negative acceleration value. 
 
 
     
     
       10. The vehicle of  claim 9 , further including a hitch receiver coupled with the vehicle, wherein:
 the external communication coupling is a wiring harness one of on or adjacent the hitch receiver. 
 
     
     
       11. The vehicle of  claim 9 , wherein the external communication coupling is a wireless transmitter. 
     
     
       12. The vehicle of  claim 9 , wherein the signal output by the position sensor is proportionate to the position of the vehicle brake pedal with respect to the range of movement. 
     
     
       13. The vehicle of  claim 12 , wherein:
 the trailer brake controller is included in a vehicle brake system that further includes a plurality of vehicle brake units; and 
 the vehicle brake system causes actuation of the plurality of vehicle brake units at a predetermined level correlating with the position of the brake pedal. 
 
     
     
       14. The vehicle of  claim 9 , wherein the controller adjusts the initial trailer brake torque demand according to a closed loop control scheme. 
     
     
       15. The vehicle of  claim 9 , wherein the predetermined formula provides the expected negative acceleration value as a function of the signal from the position sensor. 
     
     
       16. A trailer brake control method, comprising:
 receiving a position signal from a position sensor indicating a position of a vehicle brake pedal and deriving an initial trailer brake torque demand signal correlated with the position signal; 
 outputting the initial trailer brake torque demand signal to a trailer brake module; 
 determining an expected negative acceleration value for the vehicle correlated with the position signal from the position sensor using one of a predetermined formula or a table; 
 receiving a vehicle acceleration signal from a vehicle acceleration sensor; and 
 adjusting the initial trailer brake torque demand signal to converge the vehicle acceleration signal to the expected negative acceleration value. 
 
     
     
       17. The method of  claim 16 , wherein the position signal from the position sensor is proportionate to the position of the brake pedal with respect to the range. 
     
     
       18. The method of  claim 17 , wherein:
 the trailer brake controller is included in a vehicle brake system that further includes a plurality of vehicle brake units; and 
 outputting the initial brake torque demand signal causes the plurality of vehicle brake units to actuate at a predetermined level correlating with the application position of the brake pedal. 
 
     
     
       19. The method of  claim 16 , wherein adjusting the initial trailer brake torque demand is implemented according to a closed loop control scheme. 
     
     
       20. The method of  claim 16 , wherein the predetermined formula provides the expected negative acceleration value as a function of the position signal from the position sensor.